Propeller



Feb. 6, 1968 c. w. VAN RANST 3,367,423

PROPELLER Filed June 13, 1966 INVENTOR CORNELIUS w. VAN RANST UnitedStates Patent 3,367,423 PROPELLER Cornelius W. Van Ranst, 15692Woodland, Dearborn, Mich. 48120 Filed June 13, 1966, Ser. No. 557,222 2Claims. (Cl. 170-159) The present invention relates to propellers formotor boats, and especially to improvements in propellers of the typereferred to as Weedless propellers.

It is known to provide propellers which are shaped so as to reduce to aminimum the tendency of weeds, and the like, to be caught and retainedon a propeller of a boat when the propeller turns in weed infestedwaters. Normally, such propellers function satisfactorily when rotatingin a forward direction, but, because of their shapes, they cannot turnin a reverse direction without creating a severe weed-entanglementproblem.

It is an object of the present invention to provide an improved Weedlesspropeller, and particularly one which is adapted to provide optimumWeedless conditions of operation when turning in either direction ofrotation.

It is another object of the present invention to provide a propeller ofthe foregoing character which is characterized by its efficientoperation when turning in either direction of rotation.

It is still another object of the present invention to provide apropeller which is constructed and arranged so that it can bemanufactured at relatively low cost, and one which is relatively lightin weight.

According to the present invention, a propeller is provided which has ahub portion and a plurality of blades radiating therefrom, with eachblade having a leading edge, an outer circumferential edge and atrailing edge shaped to provide optimum Weedless conditions irrespectiveof the direction of rotation of the propeller. In a preferred form ofthe invention, the leading edge defines a line which is a continuousrearward progression from its origin at the hub portion to itstermination at the circumferential edge, and the trailing edge definessubstantially a straight line inclined rearwardly from its origin at theouter circumferential edge and to its termination at the hub portion. Inthis form of the invention, the circumferential edge defines a linewhich is located on a constant radius from the axis of the hub portion.It is also contemplated that the individual blades can be made fromsheet metal stampings which will be suitably secured to the hub portion,as by a welding operation. In this form of the invention each blade willhave a uniform thickness throughout its entire surface.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

In the drawing:

FIGURE 1 is a rear end elevation of a propeller embodying the presentinvention;

FIGURE 2 is an enlarged fragmentary end elevation illustrating one ofthe blades of the propeller with dotted lines in the figure toillustrate the manner in which the edges of the blades are established;

FIGURE 3 is a fragmentary top plan view of the blade illustrated in FIG.2;

FIGURE 4 is a fragmentary side elevation of the blade illustrated inFIGS. 2 and 3; and

FIGURE 5 is a developed blade, showing its shape in a sheet metal blankprior to being warped to the shape of the blade illustrated in FIGS. 2,3 and 4.

Before explaining the present invention in detail, it is to beunderstood that the invention is capable of other embodiments and ofbeing practiced or carried out in various ways. It is also to beunderstood that the phraseology or terminology employed herein is forthe purpose of description and not of limitation.

Referring now to the drawing, the invention will be described in greaterdetail. The propeller 10 comprises a hub portion 12 from which theblades 14, 16 and 18 radiate. Any suitable hub portion construction maybe employed, and for a more detailed description of the hub portion 12,reference is made to copending application Ser. No. 557,- 227, filedJune 13, 1966, for Propeller Assembly. The propeller blades 14, 16 and18 are suitably secured to the outer sleeve 20 of hub portion 12 by awelding operation. Each of the blades 14, 16 and 18 have the sameconfiguration, and therefore only blade 14 will be described in detail.As shown in the drawing, the propeller blade 14 has a leading edge 22which originates at the hub portion 12 and terminates at thecircumferential edge 24. The circumferential edge 24 defines the shapeof the propeller at the outer circumference and this edge extendsrearwardly to the trailing edge 26 which extends radially inwardly untilit terminates at the hub portion 12. As can be seen best in FIG. 2, theleading edge 22 defines a line which is a continuous rearwardprogression from its origin at the hub portion 12 to its termination atthe circumferential edge 24. Thus, there is no portion on the leadingedge where weeds or the like can be caught or trapped so as to entanglethe propeller blade.

As also can be seen best in FIG. 2, the circumferential edge 24 definesa line which remains at a constant radius from the axis 28 of the hubportion 12. Similarly, the trailing edge 26 can be seen to besubstantially a straight line from the terminal edge of thecircumferential edge 24 to its point of termination on the hub portion12. The trailing edge 26 is inclined rearwardly at a uniform slope fromits point of origin at circumferential edge 24 to its point oftermination on hub portion 12. Thus, this trailing edge also does nothave any portion of its length on which weeds or the like can be snaggedor retained when the propeller 10 is rotating in a reverse direction.

In forming the propeller blade 14, it is preferred that it be made froma sheet metal stamping or blank 30 shown in its developed or fiat shapein FIG. 5. For the purpose of establishing the shape of blank 30, theoptimum shape of the blade 14 is initially determined, as shown in FIG.2, wherein the dotted radial lines 32, which are at ten degreeintervals, are shown intersecting circular lines 34 which increase inradius in uniform increments so as to define a line, passing through thepoints of intersection, having a continuous rearward progression. Sevenof such ten degree intervals are provided for establishing the line.Thereafter the outer circumferential edge 24 is determined by extendingtwo more of such ten degree intervals from the same center, and the edge24 is defined by an arc of a circle having the same center. The trailingedge 26 is established by extending a substantially straight line fromthe end of the edge 24 to a point on hub portion 12 which is ten degreesbeyond the last ten degree interval used in defining the are for theedge 24. The pitch of the propeller can be varied depending on the usethat is to be made of the propeller. If it is to be used in connectionwith a light load, a higher pitch may be employed than is the case whenthe boat that is to be propelled is relatively heavy, in which case alower pitch will be employed. The extent of the pitch to be employedwill thus vary in a manner well known to those skilled in the art.

Having established the desired shape of a blade 14, a developed shapecan be projected therefrom which will be essentially the shape of theblank 30 shown in FIG. 5. This shape will then be used as a pattern bywhich the blank 30 can be formed in a stamping operation. After theblanks 30 have been formed, they will be warped to the illustrated shapeof the blade 14, and thereafter the 3 blades 14, 16 and 18 can be weldedto the outer sleeve 20 by any suitable means.

From the foregoing description, it will be observed that an improvedpropeller has been provided which can be turned either in a forward orin a rearward direction without having surfaces or edges on which weedscan be caught and entangled. The propeller blades also have maximumsurface areas at their outer circumferences so as to provide optimumworking conditions for the propeller for turning in both directions. Thepropeller is light in weight and can be economically produced so as toprovide a relatively low cost unit.

Having thus described my invention, I claim:

1. A propeller having a hub portion and three blades of uniformthickness throughout radiating therefrom, each blade overlying 100degrees of the circumference of the hub portion and having in sequence aleading edge which overlies 70 degrees of said circumference, an outercircumferential edge which overlies 20 degrees of said circumference anda trailing edge which overlies degrees of said trailing edge defining asubstantially straight line inclined rear'wardly from its origin at saidouter circumferential edge to its termination at said hub portion.

2. A propeller according to claim 1, wherein said blades are integrallyjoined to said hub portion by welded joints.

References Cited UNITED STATES PATENTS 2,011,821 8/1935 Meyers et a1l-159 2,378,049 6/1945 Upson 159' 2,390,879 12/1945 Hagen 1701593,023,709 3/1962 Kondo 170-159 X FOREIGN PATENTS 527,573 7/1921 France.

764,860 3/1934 France. 1,065,181 12/1953 France.

949,899 9/1956 Germany.

511,932 8/ 1939 Great Britain.

683,012 11/ 1952 Great Britain.

39,355 7/ 1924 Norway.

EVERETTE A. POWELL, IR., Primary Examiner.

MARTIN P. SCHWADRON, Examiner.

1. A PROPELLER HAVING A HUB PORTION AND THREE BLADES OF UNIFORMTHICKNESS THROUGHOUT RADIATING THEREFROM, EACH BLADE OVERLYING 100DEGREES OF THE CIRCUMFERENCE OF THE HUB PORTION AND HAVING IN SEQUENCE ALEADING EDGE WHICH OVERLIES 70 DEGREES OF SAID CIRCUMFERENCE, AN OUTERCIRCUMFERENTIAL EDGE WHICH OVERLIES 20 DEGREES OF SAID CIRCUMFERENCE ANDA TRAILING EDGE WHICH OVERLIES 10 DEGREES OF SAID CIRCUMFERENCE, SAIDLEADING EDGE DEFINING A LINE WHICH IS A CONTINUOUS REARWARD PROGRESSIONFROM ITS ORIGIN AT THE HUB PORTION TO ITS TERMINATION AT THECIRCUMFERENTIAL EDGE, SAID CIRCUMFERENTIAL EDGE DEFINING A LINE WHICH ISSUBSTANTIALLY A CONSTANT RADIUS FROM THE AXIS OF SAID HUB PORTION, SAIDTRAILING EDGE DEFINING A SUBSTANTIALLY STRAIGHT LINE INCLINED REARWARDLYFROM ITS ORIGIN AT SAID OUTER CIRCUMFERENTIAL EDGE TO ITS TERMINATION ATSAID HUB PORTION.